Summary AQA A Level Biology-The general properties of Proteins- Unit 1

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General properties of proteins

Introducing proteins and amino acids:
Proteins are organic molecules with many important functions.

Structural roles- e.g. muscles- form the structure of tendons

Metabolic roles- e.g. enzymes catalyse reactions

Transport roles- e.g haemoglobin transports oxygen

Made of carbon, hydrogen and oxygen like carbohydrates- but also contain
other elements like nitrogen and sometimes sulphur and phosphorus.


Amino Acids:
The building blocks used to make proteins- monomers.

Polymer of amino acids= protein.
All amino acids have the same basic strucure:




Central carbon (C) atom




General properties of proteins 1

, Bonded to a carboxyl group (-COOH)

An amino (amine) group (-NH2)

A hydrogen group (-H)

And an R group (-R)



Each amino acid (20 different types) has a different R group- everything else is
the same.



💡 Amino acids are the monomer units to make proteins. All amino acids
have the same basic strucutre but with different R groups.


R groups can vary in their:

Size- e.g glycine and lysine (don’t have to learn)




Polarity- polar molecules have an area with a positive charge and an area
with a negative charge.- e.g. Alanine and cysteine.




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